Releasing material and release agent

ABSTRACT

It is an object of the present invention to provide a release material and a release agent, which can be produced by directly coating onto a substrate without requiring the application of an undercoating material even when using a permeable substrate such as paper, which have excellent releasability even when the amount of silicone used is small, have a low change in peel strength over time, have a high residual adhesion ratio of an adhesive tape, seal and the like after release from a release material, and have writability or printability to a release surface. A release material and a release agent are provided, wherein the release layer contains a neutralized resin obtained from a neutralization reaction of an emulsion copolymer of a monomer composition containing from 5 to 80 mass % of an unsaturated carboxylic acid monomer with a basic substance, and a silicone emulsion and/or a silicone dispersion.

TECHNICAL FIELD

The present invention relates to release materials such as releasepaper, release film, releasable cloth and the like, which are used initems such as adhesive tape and Kraft tape, and also used in items suchas adhesive sheet boards and adhesive labels. Also, the presentinvention relates to a release agent used in the production thereof.

BACKGROUND ART

In the field of adhesive tape, Kraft tape, adhesive labels, adhesiveseals, adhesive sheets and the like, release materials as represented byrelease paper are widely used. Such release materials can be producedusing a method of directly coating a release agent solution consistingmainly of a solvent type, a non-solvent type or an emulsion typesilicone resin onto a substrate such as paper. However, this method hasthe problem that the amount of silicone resin used is large, because incase that the substrate is permeable (for example, paper), the coatingsolution permeates into the substrate. To suppress permeation of thecoating solution, it is currently mainstream to laminate the substratewith polyethylene, and coat a solvent-type silicone resin on top ofthat. However, in recent years the need to recycle paper fortransformation into recycled paper has developed from the standpoint ofresource and environmental concerns. To achieve that, it has becomedesirable to use a method that does not use a polyethylene laminate,which has low recoverability. Specifically, methods have been proposedin which in place of polyethylene a latex, such as SB latex or acryliclatex (JP-A-2001-2975), or a water-soluble resin, such as polyvinylalcohol (JP-A-5-279995) is applied onto the substrate as an undercoatingmaterial, wherein the silicone resin is then applied. However, thismethod is not satisfactory in terms of performance and productivity.Another method that has been proposed directly applies a mixture of anaqueous emulsion and a silicone compound for hardening (JP-3-500060T);but this method has the drawbacks of insufficient releasability andincrease of peel strength over time. Furthermore, for example, thismethod has the drawbacks that if the amount of silicone compound used isnot increased, releasability is not exhibited.

Thus, the provision of a writable, printable release material has beendesired wherein permanent ink, aqueous ink, an inkjet printer, athermal-transfer printer and the like can be used on a release surfaceof Kraft tape, tack paper and the like. While methods that use asilicone resin as the release agent provide good releasability, theirwriting and printing properties are insufficient. On the other hand,while excellent writability and printability can be achieved when anon-silicone compound such as a compound containing long chain alkylgroups is used as the release agent, the releasability is insufficient.Until now there has not been a release material satisfying releasabilitytogether with writability and printability.

It is an object of the present invention to provide a release material,and a release agent used in the production thereof, which:

-   -   can be produced by directly coating onto a substrate without        requiring the application of an undercoating material even when        using a permeable substrate such as paper;    -   has excellent releasability even when the amount of silicone        used is small;    -   has a low change in peel strength over time;    -   has a high residual adhesion ratio of an adhesive tape, seal and        the like after release from a release material; and    -   has a surface which is writable or printable.

DISCLOSURE OF THE INVENTION

The present inventors, as a result of various investigations to solvethe above problem, accomplished the present invention by finding thatthe release material disclosed below, which comprises, in a releaselayer, a neutralized resin obtained from a specific emulsion copolymer,and a silicone emulsion and/or a silicone dispersion. That is, thepresent invention relates to:

(1) A release material comprising a substrate and a release layer onsaid substrate, wherein a surface portion of said release layer has asilicone layer having a thickness of from 1 to 100 nm.

(2) The release material according to item 1, wherein the silicone layerof the surface portion of said release layer has a thickness of from 1to 50 nm.

(3) A release material comprising a substrate and a release layer onsaid substrate, wherein said release layer comprises a polymer having acarboxylate group and a silicone.

(4) A release material comprising a substrate and a release layer onsaid substrate, wherein said release layer is prepared using:

-   -   (A) a neutralized resin obtained from a neutralization reaction        of an emulsion copolymer of a monomer composition containing        from 5 to 80 mass % of an unsaturated carboxylic acid monomer        with a basic substance; and    -   (B) a silicone emulsion and/or a silicone dispersion.

(5) The release material according to item 4, wherein said (B) siliconeemulsion and/or a silicone dispersion has a number average particlediameter of 200 nm or less as measured by dynamic light scattering.

(6) The release material according to any one of items 4-5, wherein theneutralized resin is water-soluble.

(7) The release material according to any one of items 4 to 6, whereinthe unsaturated carboxylic acid monomer is acrylic acid and/ormethacrylic acid.

(8) The release material according to any one of items 4 to 7, whereinthe basic substance is ammonia.

(9) The release material according to any one of items 4 to 8, whereinthe neutralized resin has a pH of from 3 to 13.

(10) The release material according to any one of items 4 to 9, whereinsaid release layer has a surface portion silicone layer having athickness of from 1 to 100 nm.

(11) The release material according to item 10, wherein said releaselayer has a surface portion silicone layer having a thickness of from 1to 50 nm.

(12) A release material comprising a substrate and a release layer onsaid substrate, wherein the surface silicon atomic concentration of saidrelease layer as measured by an XPS (X-ray Photoelectron Spectroscope)is from 10 to 30 atom %.

(13) The release material according to any one of items 1 to 11, whereinthe surface silicon atomic concentration of said release layer asmeasured by an XPS (X-ray Photoelectron Spectroscope) is from 10 to 30atom %.

(14) The release material according to item 12 or 13, wherein thesilicone content of the release layer is from 1 to 90 mass %.

(15) The release material according to item 14, wherein the siliconecontent of the release layer is from 1 to 50 mass %.

(16) A release material comprising a substrate and a release layer onsaid substrate, wherein the surface silicon atomic concentration of saidrelease layer as measured by an XPS (X-ray Photoelectron Spectroscope)is at least 5 times greater than the average silicon atomicconcentration of the release layer as calculated from the siliconecontent of said release layer.

(17) The release material according to any one of items 1 to 15, whereinthe surface silicon atomic concentration of said release layer asmeasured by an XPS (X-ray Photoelectron Spectroscope) is at least 5times greater than the average silicon atomic concentration of therelease layer as calculated from the silicone content of said releaselayer.

(18) The release material according to item 16 or 17, wherein theaverage silicon atomic concentration of the release layer as calculatedfrom the silicone content of said release layer is from 0.2 to 4 atom %.

(19) The release material according to any one of items 1 to 18, whereinthe silicone in said release layer is a curable silicone.

(20) The release material according to any one of items 1 to 19, whereinthe silicone in said release layer substantially comprises a curedmaterial obtained from an Si—H group-containing silicone and a vinylsilicone.

(21) The release material according to any one of items 1 to 20, whereinthe substrate is selected from the group consisting of paper, cloth,resin laminated paper, resin coated paper, a resin film, a resin tapeand a resin sheet.

(22) The release material according to item 21, wherein the substrate iseither paper or cloth.

(23) A release agent comprising a polymer having a carboxylate group anda silicone.

(24) The release agent according to item 23, wherein the siliconecomprises a silicone in the state of a silicone emulsion and/or siliconedispersion.

(25) A release agent comprising:

-   -   (A) a neutralized resin obtained from a neutralization reaction        of an emulsion copolymer of a monomer composition containing        from 5 to 80 mass % of an unsaturated carboxylic acid monomer        with a basic substance; and    -   (B) a silicone emulsion and/or a silicone dispersion.

(26) The release agent according to item 24 or 25, wherein said (B)silicone emulsion and/or a silicone dispersion has a number averageparticle diameter of 200 nm or less as measured by dynamic lightscattering.

(27) The release material according to any one of items 23 to 26,wherein the silicone content is from 1 to 90 mass % based on the totalsolids content of the release agent.

(28) The release agent according to item 27, wherein the siliconecontent is from 1 to 50 mass % based on the total solids content of therelease agent.

(29) The release agent according to any one of items 25 to 28, whereinthe neutralized resin is water-soluble.

(30) The release agent according to any one of items 25 to 29, which isprepared by mixing:

-   -   (C) a release agent stock solution C, which comprises (c-1) a        neutralized resin obtained from a neutralization reaction of an        emulsion copolymer of a monomer composition containing from 5 to        80 mass % of an unsaturated carboxylic acid monomer with a basic        substance; and (c-2) a silicone emulsion and/or a silicone        dispersion containing vinyl silicone and a group VIII metal        compound; with    -   (D) a release agent stock solution D, which comprises a silicone        emulsion and/or silicone dispersion containing a Si—H        group-containing silicone.

(31) A method of producing a release material, comprising the steps ofapplying the release agent according to any one of items 23 to 30 onto asubstrate and drying it.

(32) The method of producing a release material according to item 31,wherein said drying is carried out at a temperature of from 100 to 250°C.

(33) The method of producing a release material according to item 31 or32, wherein the substrate is selected from the group consisting ofpaper, cloth, resin laminated paper, resin coated paper, a resin film, aresin tape and a resin sheet.

(34) The method of producing a release material according to item 33,wherein the substrate is either paper or cloth.

(35) An adhesive tape comprising a substrate, a release layer on oneside of said substrate and an adhesive layer on the other side thereof,wherein said substrate and said release layer constitute the releasematerial according to any one of items 1 to 22.

(36) A method of producing an adhesive tape, which tape comprises asubstrate, a release layer on one side of said substrate and an adhesivelayer on the other side thereof, wherein the release material comprisingsaid release layer and said substrate are produced according to theproduction methods of a release material according to any one of items31 to 34.

(37) The adhesive tape according to item 35 or the method of producingan adhesive tape according to item 36, wherein the adhesive layer is awater-soluble or water-dispersible adhesive, or an alkali-soluble oralkali-dispersible adhesive.

(38) An adhesive sheet comprising a release substrate; a release layeron said release substrate; and an adhesive layer and a surface substratelaminated on said release layer in that order, wherein said releaselayer and said release substrate constitute the release materialaccording to any one of items 1 to 22.

(39) A method of producing an adhesive sheet, which sheet comprises arelease substrate; a release layer on said release substrate; and anadhesive layer and a surface substrate laminated on said release layerin that order; wherein the release material comprising said releaselayer and said release substrate are produced according to theproduction methods of a release material according to any one of items31 to 34.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a transmission electron microscope photograph (magnified250,000 times) of a release layer cross-section for a release testpiece. The lower side of the middle is the release layer, wherein asilicone layer having an average thickness of 5 nm is present on thesurface layer of the release layer.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be specifically explained.

In the present invention, a release layer is provided on a surface ofthe release material. The release layer according to the presentinvention can be provided directly on the substrate. Alternatively whereappropriate a polyethylene laminate layer, an undercoating layer or etc.may be provided on the substrate and the release layer can be providedthereon. However, in terms of recycling efficiency and productivity, itis preferable to provide the release layer according to the presentinvention directly on the substrate.

The release material according to the present invention comprises asubstrate and a release layer thereon. The surface layer portion of therelease layer preferably comprises a silicone layer having a thicknessof from 1 to 100 nm. More preferably the thickness of the silicone layeris from 1 to 50 nm and still more preferably from 1 to 20 nm. Thethickness of the silicone layer is the average value as determined by atransmission electron microscope. The above range is preferable becausewhen the thickness of the silicone layer is within such a range,releasability as well as writability and printability are good.According to the present invention, a release material in which thesilicone layer is unevenly distributed or localized on such a releaselayer surface can be obtained.

The release layer of the release material according to the presentinvention may comprise a silicone constituent other than the siliconelayer of the surface layer portion of the release layer. In such a case,it is preferable that a continuous layer of a polymer having acarboxylate group, which will be described below, is present in thelayer of the surface portion other than the silicone layer. Morepreferable is a configuration in which the silicone is dispersed in thecontinuous layer.

When there is essentially no silicone contained in the layer of thesurface portion other than the silicone layer, the amount of expensivesilicone can be reduced, and the writability and printability are good,which is preferable.

The release material according to the present invention has preferablyfrom 10 to 30 atom % of surface layer silicon atomic concentration ofthe release layer as measured by an XPS (X-ray PhotoelectronSpectroscope), has more preferably from 10 to 25 atom %, and has stillmore preferably from 15 to 25 atom %. Especially preferable is from 22to 25 atom %. When the surface layer silicon atomic concentration iswithin such a range, releasability as well as writability andprintability are good.

In the present invention, the average silicon atomic concentration ofthe release layer as calculated from the silicone content ratio of thetotal solids content of the release layer is preferably from 0.2 to 4atom %. The surface layer silicon atomic concentration as measured by anXPS (X-ray Photoelectron Spectroscope) is preferably at least 5 timesgreater than the average silicon atomic concentration of the releaselayer, and more preferably at least 10 times greater. When theconcentration is within such a range, a release material can be obtainedthat is excellent in releasability as well as writability andprintability even if the amount of silicone used is small. According tothe present invention, even when the silicone content ratio of the totalsolids content of the release layer is low i.e., 1 to 20 by mass %, arelease material having a surface layer silicon atomic concentration of13 to 24 atom %, which is far greater than the average silicon atomicconcentration of from 0.2 to 4 atom % in the release layer as calculatedfrom said silicone content, can be obtained, and as a resultreleasability becomes good. Since a material having good releasabilityin the present invention can be obtained even if a small amount ofexpensive silicone is used, the economical efficiency is advantageous.Further, because of excellent writability and printability, the presentinvention is particularly superior to the conventional art.

The atom % which shows the silicon atomic concentration in the presentinvention represents the percentage of silicon atoms on the basis of thetotal of all of the number of atomic quantitative values having anatomic number greater than or equal to the atomic number of a carbonatom as measured by an XPS (X-ray Photoelectron Spectroscope). The XPS(X-ray Photoelectron Spectroscope) used for measuring irradiates X-raysat a test sample and then analyzes the kinetic energy of photoelectronsemitted from the surface. While there are no restrictions on the devicethat may be used as long as it can analyze the characteristics of theelements that are present on the sample surface layer (analysis depth:several nm), their amounts and their chemical states, an ESCALAB 250made by Thermo VG can be shown as an example.

In the present invention, as to the release material which comprises asubstrate and a release layer on the substrate, the release layerpreferably comprises a polymer having a carboxylate group and asilicone. Compared with the use of a water-soluble resin such aspolyvinyl alcohol, using a polymer having a carboxylate group achievessuperior releasability, suppression of change with time, improvedresidual adherence, writability and printability on the release surface.While the polymer having a carboxylate group used in the presentinvention is not particularly restricted, a totally or partiallyneutralized polymer which contains a carboxylic acid group obtained bypolymerizing a monomer composition which contains an unsaturatedcarboxylic acid monomer can be shown as an example.

In the present invention, as to the release material which comprises asubstrate and a release layer on said substrate, the release layer ispreferably the release material which comprises (A) a totally orpartially neutralized product of a polymer having a carboxylic acidgroup, and (B) a silicone emulsion and/or silicone dispersion. In thepresent invention it is preferable to use a polymer in which some or allof the carboxylic acid groups of the polymer have been neutralized usinga base. Compared with the use of a water-soluble resin such as polyvinylalcohol, the use of a polymer neutralized product according to thepresent invention in the release agent layer can achieve superiorreleasability, suppression of change with time, improved residualadherence, writability and printability on the release surface. Whilethe polymer having a carboxylic acid group used in the present inventionis not particularly restricted, the emulsion copolymer of a monomercomposition which contains an unsaturated carboxylic acid monomer can beshown as an example.

In the present invention, while the ratio of silicone content to thetotal solids content of the release layer is not particularlyrestricted, from 1 to 90 mass % is preferable. A silicone content of 1mass % or more is preferable in terms of development releasability, 5mass % or more is further preferable and 10 mass % or more is stillfurther preferable. Also, a content of 90 mass % or less is economicallypreferable because the amount of expensive silicone used is lower, whilea content of 50 mass % or less is more preferable in terms ofwritability and printability, 30 mass % or less is still more preferableand 20 mass % or less is especially preferable. The present invention isexcellent in release properties with a lower silicone content ascompared to the prior art, and is characterized in being superior inwritability and printability. Also, the content of the polymer having acarboxylate group used in the present invention is preferably from 10 to99 mass %. More preferable is 95 mass % or less and 90 mass % or less isstill more preferable. A content of 10 mass % or more is preferable,more preferable is 50 mass % or more, 70 mass % or more is still morepreferable and 80 mass % or more is especially preferable. When thecontent of the polymer having a carboxylate group is within such arange, releasability as well as writability and printability are good,and so is preferable.

The release agent according to the present invention comprises a polymerhaving a carboxylate group and silicone. The release agent according tothe present invention can be preferably used to produce the releasematerial according to the present invention.

The release agent according to the present invention preferablycomprises a neutralized resin which can be obtained from theneutralization reaction of an emulsion copolymer of a monomercomposition containing from 5 to 80 mass % of an unsaturated carboxylicacid monomer with a basic substance. By including a constituent derivedfrom a specific neutralized resin in the release layer using the releaseagent superior releasability, suppression of change over time, improvedresidual adherence, and writability and printability on the releasesurface can be achieved.

The polymer having a carboxylate group used in the present inventionpreferably has from 5 to 80 mass % of a mass fraction of the unsaturatedcarboxylate monomer based on all the monomers used in polymerization,more preferably from 10 to 60 mass % and still more preferably from 15to 50 mass %. The mass fraction of the unsaturated carboxylate monomeris preferably within this range because emulsion stability as well aswater solubility and swelling property of the resin constituent obtainedfrom the neutralization reaction of the emulsion are good. The polymerhaving a carboxylate group used in the present invention can beobtained, for example, by means of the total or partial neutralizationof a product prepared from an unsaturated carboxylic acid monomer, andif necessary, a monomer composition containing other polymerizablemonomers according to an ordinary emulsion polymerization method.

The emulsion copolymer used in the present invention (herein “emulsioncopolymer” being referred to as copolymer in the state of emulsion)preferably has a mass fraction of the unsaturated carboxylic acidmonomer based on all the monomers used in the polymerization of from 5to 80 mass %, more preferably from 10 to 60 mass % and still morepreferably from 15 to 50 mass %. When the mass fraction of theunsaturated carboxylic acid monomer is within this range, emulsionstability as well as water solubility and swelling property of theneutralized resin obtained from the neutralization reaction of theemulsion are good and so is preferable. The emulsion copolymer used inthe present invention can be prepared according to an ordinary emulsionpolymerization method from an unsaturated carboxylic acid monomer andoptionally, a monomer composition containing other polymerizablemonomers.

While the unsaturated carboxylic acid monomer used in the presentinvention is not particularly restricted as long as it has a carboxylicacid group and polymerizable double bonds, examples include anunsaturated monocarboxylic acid monomer such as acrylic acid andmethacrylic acid; an unsaturated polycarboxylic acid monomer such asitaconic acid, fumaric acid and maleic acid; and an ester whichmaintains one or more of these carboxylic acid groups. From thestandpoint of development of releasability and coating properties,acrylic acid or methacrylic acid is preferably used. These unsaturatedcarboxylic acid monomers can be used in a combination of two or more.

The polymer having a carboxylic acid group, the polymer having acarboxylate group and other polymerizable monomers used in the emulsioncopolymer, all of which are used in the present invention, are notparticularly restricted as long as they can copolymerize with theunsaturated carboxylic acid monomer. Examples thereof include vinylacetate, styrene, a-methyl styrene, ethylene, isoprene, butadiene, vinylchloride, acrylic esters such as methyl acrylate, ethyl acrylate, butylacrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate, methacrylicesters, such as methyl methacrylate, ethyl methacrylate, butylmethacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, amidederivatives such as acrylamide, acrylonitrile, and methacrylonitrile.From the standpoint of development of releasability and coatingproperties, acrylic ester and methacrylic ester are preferably used.These polymerizable monomers can be used singly or in combination.

While the glass transition point temperature for the polymer having acarboxylic acid group, the polymer having a carboxylate group and theemulsion copolymer, all of which are used in the present invention, isnot particularly restricted, from the standpoint of coating propertiessuch as coating strength and releasability, it is preferably from −35°C. to 140° C. and more preferably from −25° C. to 100° C.

The release agent according to the present invention contains aneutralized resin (A) which is obtainable by the neutralization of theemulsion copolymer with a basic substance. Although the emulsioncopolymer emulsifies and disperses in water in particle form underacidic conditions of a pH of less than 3, it dissolves or swells inwater, when the pH is raised by adding a basic substance. Theneutralized resin used in the present invention is water-soluble or asubstance that has water-swelling properties. The basic substance usedin the present invention is not particularly restricted as long as itdissolves or swells the emulsion copolymer in water by theneutralization reaction of the unsaturated carboxylic acid moiety of theemulsion copolymer. Examples of the basic substance include metalhydroxides such as lithium hydroxide, sodium hydroxide and potassiumhydroxide; fatty amine compounds such as ammonia, ethylamine,diethylamine, triethylamine, cyclohexylamine, allylamine,ethylenediamine, triethylenetetramine, and ethanol amine; and aromaticamines such as an aniline. From the standpoint of releasability,residual adhesion property and coating property, ammonia or fatty aminecompounds are preferably used, and ammonia is especially preferablyused. Releasability and residual adhesion can be improved by dissolvingor swelling the emulsion copolymer in water using the basic substance.Preferable in terms of releasability and residual adhesion is the casewhere a basic substance is used to dissolve the emulsion copolymer inwater, in other words, the case where the neutralized resin according tothe present invention is water-soluble.

In the present invention, while the pH of the neutralized resin afterthe neutralization reaction of the emulsion copolymer with a basicsubstance is not particularly limited, from 3 to 13 is preferable, 5 to12 is more preferable and 6 to 10 is still more preferable. The pH ispreferably within this range because releasability, residual adhesionand water solubility and swelling property of the resin constituentobtained by the emulsion neutralization reaction are good. While themethod of neutralization reaction in the present invention is notparticularly limited, a method of adding and stirring an aqueoussolution of a basic substance to the emulsion copolymer until thedefined pH is reached can be shown as an example. The concentration ofthe aqueous solution of the basic substance to be added is notparticularly restricted, but is preferably from 1 to 20 mass %, morepreferably from 2 to 10 mass % in order to obtain a suitable releaseagent concentration and to avoid thickening and gelling due to localizedneutralization reactions.

While the emulsion copolymer concentration in the release agentaccording to the present invention is not particularly limited, in orderto obtain a suitable release agent viscosity, from 1 to 50 mass % ispreferably used, and from 5 to 40 mass % is more preferably used.

The release agent according to the present invention preferablycomprises (B) a silicone emulsion and/or a silicone dispersion. Therelease agent preferably comprises (B) a silicone emulsion and/or asilicone dispersion (when only one of them is used, this means theindividual number average particle diameter, and when a mixture of themis used, this means the number average particle diameter of the mixture)having a number average particle diameter of 200 nm or less as measuredby dynamic light scattering. By including a silicone compound in therelease layer using the release agent, releasability can be developed.The silicone compound used in the release agent according to the presentinvention is preferably in an emulsion or dispersion state andpreferably has a number average particle diameter for (B) the siliconeemulsion and/or silicone dispersion as measured by dynamic lightscattering of 200 nm or less. Further, the number average particlediameter for (B) the silicone emulsion and/or silicone dispersion ispreferably from 1 to 200 nm. The number average particle diameter ispreferably 200 nm or less because the peel strength becomes very lowcompared with the case when the particle diameter is large. The numberaverage particle diameter is preferably 1 nm or more because preparationof (B) the silicone emulsion and/or silicone dispersion is made easy.The number average particle diameter is especially preferably from 1 to100 nm because releasability is further improved. It is not clear whythe peel strength gets smaller when the number average particle diameteris 200 nm or less, but it is conjectured that releasability improvesbecause the silicone constituent tends to become localized on thesurface during release layer formation when the number average particlediameter of the silicone emulsion and/or silicone dispersion is 200 nmor less.

The silicone emulsion used in the present invention is obtained byemulsifying a silicone compound in a solvent using a surfactant such asa nonionic type emulsifier. The silicone dispersion is obtained bydispersing a silicone compound in a solvent using modification due to ahydrophilic group and the like without the use of a surfactant.

While the silicone used as the silicone emulsion or silicone dispersionaccording to the present invention is not particularly limited, examplesinclude silicone oils such as a Si—H group-containing silicone,dimethylpolysiloxane, methylphenyl polysiloxane, alkoxy group-containingsilicone, silanol group-containing silicone,octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane; andmodified silicones such as vinyl silicone, polyether modified silicone,polyglycerin modified silicone, amino modified silicone, epoxy modifiedsilicone, mercapto modified silicone, methacrylic modified silicone,carboxylic-acid modified silicone, fatty-acid-ester modified silicone,alcoholic modified silicone, alkyl modified silicone, fluoroalkylmodified silicone and photopolymerizable functional group modifiedsilicone. These silicones may be present individually, or two types ormore may coexist together.

The silicone used in the present invention preferably is a curablesilicone. Using a curable silicone improves releasability, allows thechange in peel strength over time to be suppressed, and increases theresidual adhesion ratio. The curable silicone is not particularlylimited as long as it can cure by heat, ultraviolet rays, an electronbeam and the like. Examples include addition type curing from a Si—Hgroup-containing silicone and a vinyl silicone, condensation type curingfrom a Si—H group-containing silicone and a silanol group-containingsilicone, and UV curing from a photopolymerizable functional groupmodified silicone. Especially, addition type curing from a Si—Hgroup-containing silicone and a vinyl silicone is preferable from thepoint of curability. To promote the addition type curing reaction from aSi—H group-containing silicone and a vinyl silicone reaction, it ispreferable to have a commonly known curing catalyst present. Using agroup VIII metal as a catalyst for curing is especially preferable fromthe point of curing performance. The Si—H group-containing silicone usedin the present invention is not particularly restricted, but polymethylhydrogen siloxane is preferably used.

The group VIII metal compound used in the present invention is notparticularly restricted. Examples include platinum group compounds,namely the compounds of ruthenium, rhodium, palladium, osmium, iridiumand platinum are suitable, and in particular compounds of platinum andpalladium are preferable. Examples of platinum compounds includeplatinum chloride (II), platinum chloride (IV), chloroplatinic acidssuch as tetrachloroplatinic acid (II) and hexachloroplatinic acid (IV),ammonium hexachloroplatinate (IV), potassium hexachloroplatinate (IV),platinum hydroxide (II), platinum dioxide (IV),dichloro-dicyclopentadienyl-platinum (II), a platinum-vinylsiloxanecomplex, a platinum-phosphine complex, a platinum-olefin complex, achloroplatinic acid-olefin complex, elemental platinum and a materialcarrying solid platinum on alumina, silica or active carbon. Examples ofthe palladium compound include palladium (II) chloride, ammoniumtetraammine-chloropalladate (II) and palladium (II) oxide. Among these,a chloroplatinic acid and a chloroplatinic acid-olefin complex can bemore preferably used. The amount of group VIII metal compound used isusually from 5 to 1000 ppm of the total silicone amount.

To suppress catalytic activity of the addition curing reaction andextend the potlife of the release agent after mixing of the Si—Hgroup-containing silicone and the vinyl silicone, a reaction inhibitorcan be added to the release agent according to the present invention.Examples include organic nitrogen compounds such as a hydrazine or atriazole; organic phosphorous compounds such as a phosphine; organicsulfur compounds such as a mercaptan; and acetylene compounds such as anacetylene alcohol, cyclic methylvinylsiloxane and a siloxane modifiedacetylene alcohol.

While the ratio of the Si—H group-containing silicone to the vinylsilicone is not particularly restricted, usually it is from 0.5 to 10 ofthe ratio given by (number of Si—H mols)/(number of vinyl group mols).From a standpoint of curability, from 1.0 to 3.0 is preferably used. Asan example of a silicone compound having such a ratio of (number of Si—Hmols)/(number of vinyl group mols), silicone emulsions such as SLJ1519A/B, DEHESIVE 400 E/V20, DEHESIVE 39005VP/39006VP made by the WackerAsahi Kasei Silicone Co., Ltd. can be shown as examples.

In the present invention, the ratio of silicone content to the totalsolids content of the release agent is not particularly restricted, butis preferably from 1 to 90 mass %. A silicone content of 1 mass % ormore is preferable from the point of releasability development, 5 mass %or more is more preferable and 10 mass % or more is still morepreferable. In addition, a silicone content of 90 mass % or less iseconomically preferable because a lower amount of expensive silicone isused, while a content of 50 mass % or less is more preferable in termsof writability and printability expression, 30 mass % or less is stillmore preferable and 20 mass % or less is especially preferable. Thepresent invention is characterized in being excellent in releaseproperties while having a lower silicone content than the conventionalart, and superior in writability and printability. Also, the polymercontent having a carboxylate group used in the present invention ispreferably from 10 to 99 mass %. More preferable is 95 mass % or lessand 90 mass % or less is still more preferable. A content of 10 mass %or more is preferable, more preferable is 50 mass % or more, 70 mass %or more is still more preferable and 80 mass % or more is especiallypreferable. When the content of the polymer having a carboxylate groupis within such a range, releasability as well as writability andprintability are good, and therefore is preferable.

While the production method of the release agent according to thepresent invention is not particularly limited, a method in which theagent can be produced by, for example, mixing and stirring the siliconeemulsion and/or silicone dispersion according to the present inventioninto the neutralized resin according to the present invention can becited as an example. When the addition type curing reaction is conductedduring the course of heating and drying using a Si—H group-containingsilicone and vinyl silicone as the silicone emulsion and/or siliconedispersion, from the standpoint of shelf-life and stability of therelease solution, it is preferable to, immediately before coating, mixthe silicone emulsion and/or silicone dispersion comprising a Si—Hgroup-containing silicone and the silicone emulsion and/or siliconedispersion comprising a vinyl silicone and a curing catalyst such as aplatinum group compound, and then mix and stir by adding the liquidmixture to the neutralized resin according to the present invention forpreparation. In terms of workability, it is preferable to prepare therelease agent according to the present invention by mixing and stirringrelease stock solution C, obtained by (C) mixing and stirring thesilicone emulsion and/or silicone dispersion comprising a vinylsilicone, the curing catalyst such as a platinum group compound and theneutralized resin according to the present invention, with release stocksolution D, which comprises (D) the silicone emulsion and/or siliconedispersion comprising a Si—H group-containing silicone, just beforecoating. In the present invention, the mixing and stirring method is notparticularly restricted, but it is preferable in terms of releasabilitydevelopment to uniformly disperse the silicone emulsion and/or siliconedispersion. The mixing style and mixing time are preferably selected soas to achieve uniform dispersion.

It is possible to use solvents other than water in the release agentaccording to the present invention for improving film formability andthe like. While such solvents are not particularly restricted, examplesinclude water-soluble solvents such as alcohols, for example, ethyleneglycol monobutyl ether, propylene glycol monobutyl ether,2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and benzyl alcohol;esters, for example, diethylene glycol monobutyl ether acetate; andketones.

The release agent according to the present invention may comprise, asneeded, a polymer emulsion such as SB latex and acrylic latex; awater-soluble resin such as polyvinyl alcohol, silanol modifiedpolyvinyl alcohol, carboxyl modified polyvinyl alcohol, cation modifiedpolyvinyl alcohol, acetoacetyl modified polyvinyl alcohol, acetalmodified polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylic acid,polyacrylate, polyacrylamide, starch, casein, gelatin, carboxymethylcellulose and hydroxyethyl cellulose; a release control agent such as apolymer resin or an elastomer; pigments such as a cross linking agent, asilica, clay, and calcium carbonate; a lubricant; a silane couplingagent; a wetting agent; a defoaming agent; a thickener; a pigmentdispersion agent, and an additive.

While the substrate used in the present invention is not particularlyrestricted, examples include permeable substrates, for example papersuch as fine quality paper, Kraft paper, glassine and coated paper,cloth such as woven or non-woven fabric, timber, concrete, mortar,cement plate, brick, tile and stone; and non-permeable substrates, forexample resin laminated paper such as polyethylene laminated paper,resin coated paper which has polyvinyl alcohol, starch, SB latex or thelike coated on fine quality paper, resin films such as polypropylene andpolyethylene terephthalate, resin tape, resin sheets, plastic plates,metal plates, and metallic foil. While all of these may be used,usually, paper, cloth, resin laminated paper, resin coated paper, resinfilm, resin tape and resin sheets are preferably used. When a permeablesubstrate, for example paper such as fine quality paper, Kraft paper,glassine paper, coated paper, or cloth such as woven or non-wovenfabric, is used, it can be used without providing an undercoating layer.This substrate is especially preferable as releasability can be broughtabout with a lower amount of silicon than that in the conventional art.According to the present invention, release paper, adhesive sheets, tackpaper, labels, stickers, emblems, delivery receipts, adhesive tape,Kraft tape, process paper and the like can be preferably produced.

While the surface substrate used for the adhesive sheet according to thepresent invention is not particularly restricted, examples include papersuch as fine quality paper, coated paper, cast coated paper,thermosensitive paper and inkjet paper, cloth such as woven or non-wovenfabric, resin films such as polyvinyl chloride, synthetic paper,polyethyleneterephthalate, polypropylene, polyethylene, cellulosetriacetate, cellulose diacetate, polystyrene, polycarbonate, nylon,polyvinyl alcohol, ethylene-vinyl acetate copolymer and polyamide,porous resin films such as porous polypropylene film, metallized filmssuch as PET or polyolefin having a metal such as aluminum depositedthereon and metal foil.

While the adhesive used for the adhesive layer in the adhesive tape orthe adhesive sheet according to the present invention is notparticularly restricted, examples include natural rubber adhesives,synthetic rubber adhesives such as a styrene-isoprene-styrene blockcopolymer, a styrene-ethylene-butadiene-styrene copolymer, astyrene-butadiene-styrene block copolymer, water and alkaline-insolubletypes such as acrylic adhesives, and water-soluble or water-dispersibleadhesives and alkali-soluble or alkali-dispersible adhesives excellentin solubility and dispersibility in the course of paper recycling. Ofthese, rather than being excellent in recycling efficiency, awater-soluble or water-dispersible adhesive, an alkali-soluble oralkali-dispersible adhesive is preferably used. Examples of awater-soluble or water-dispersible adhesive include acrylicacid-containing polymers such as polyvinyl alcohol, polyacrylamide,polyvinylmethylether, ethylacrylate-acrylic acid copolymer, dextrin andpolyvinylpyrrolidone. Examples of alkali-soluble or alkali-dispersibleadhesives include metal chelate crosslinked substances of the carboxylgroup or hydroxyl group-containing monomer copolymers disclosed inJP-A-6-184508.

In the adhesive tape or adhesive sheet according to the presentinvention, as to the adhesive used on the adhesive layer, an adhesiveresin, a softener, an antioxidant and a filler are also usually used inconjunction with each other. Examples of an adhesive resin includerosins, coumarone-indenes, terpenes, petroleum, styrenes, phenols andxylenes. Examples of a softener include polybutene, polyisobutylene,polyisoprene, process oil and naphthene oils. Examples of an antioxidantinclude phenols and amines. Examples of a filler include calciumcarbonate and carbon black.

The release material according to the present invention can be producedby applying the release agent onto a substrate and drying it. Theapplication method is not particularly restricted, and a size press,blade coater, air knife coater, roll coater, brush coater, curtaincoater, bar coater, gravure coater, sprayer and the like can be used.The drying method and drying temperature are not particularlyrestricted; air drying, hot-air drying, ultraviolet radiation drying andthe like can be cited as examples, wherein the drying temperatureemployed is preferably from 80 to 250° C., more preferably from 100 to250° C. and especially preferable is from 120 to 200° C. A dryingtemperature within this range is preferable because releasability andproductivity of the drying process are good. While the applicationamount is not particularly restricted, a silicone application amount offrom 0.01 to 10 g/m² is preferable, 0.05 to 5 g/m² is more preferableand 0.1 to 1 g/m² is still more preferable. When the amount of siliconeapplication is within this range, releasability is sufficient and theamount of silicone used is low, and so this amount is economicallypreferable. After application and drying, smoothness can be adjusted bya supercalender, a gloss calendar and the like.

While the application method for the adhesive used on the adhesive tapeor adhesive sheet according to the present invention is not particularlyrestricted, a blade coater, air knife coater, roll coater, brush coater,bar coater, gravure coater, reverse coater, comma coater, kiss coaterand the like can be used. While the amount of the adhesive agent is notparticularly restricted, from 5 to 100 g/m² is preferably used and from10 to 50 g/m² is more preferably used in view of the adhesive propertyand the fact that protrusion of the adhesion from the tape or sheet doesnot occur.

Hereinafter, the present invention will be explained based on anembodiment.

The transmission electron microscope photograph was taken using atransmission electron microscope H-7100 manufactured by Hitachi, Ltd. atan acceleration voltage of 75 kV to obtain a photograph of a releaselayer cross-section, wherein an ultra-thin section had been preparedusing an ultra-microtome after embedding a test piece on an epoxy resinand curing.

The surface layer silicon atomic concentration of the release layeraccording to an XPS (X-ray Photoelectron Spectroscope) was measuredusing an ESCALAB 250 (takeoff angle of 90 degrees) made by Thermo VG.

Number average particle diameter according to dynamic light scatteringwas measured using a Microtrac UPA particle size analyzer manufacturedby Leeds & Northrup.

Evaluation of the release material was carried out by sticking adhesivetape (Nitto Denko 31B, width 5 cm) on a test piece, wherein the initialpeel strength was measured at a pulling direction of 180° and a pullingspeed of 0.3 m/min using a pulling testing machine. The change in peelstrength over time was measured in the same manner, after a test piecethat had adhesive tape stuck thereto had been stored at 23° C., 50% RHfor 14 days. The residual adhesion ratio was expressed as the percentageof a peel strength which was measured by sticking an adhesive tape ofwhich the 14-day peel strength had been measured, to an aluminum sheet,based on a peel strength which was measured by sticking an unusedadhesive tape to an aluminum sheet. The peel strength of the unusedadhesive tape was 11.8 N/5 cm. Evaluation of writability was determinedby writing on a test piece using a permanent marker, then wiping offwith tissue paper and visually observing any writing traces. Evaluationof printability was determined by printing on a test piece using acommercially available inkjet printer (PM-950C manufactured by EpsonCorp.), then wiping off with tissue paper and visually observing anyprinting traces. The evaluation standards are shown below.

(1) Releasability: Evaluated as shown below based on the initial peelstrength.

-   -   ◯: 0≦(initial peel strength)≦0.20 N/5 cm    -   Δ: 0.20<(initial peel strength)≦0.98 N/5 cm    -   X: 0.98 N/5 cm<(initial peel strength)

(2) Change in peel strength over time: Evaluated as shown below based onthe peel strength after 14 days.

-   -   ◯: 0≦(peel strength)≦0.20 N/5 cm    -   Δ: 0.20<(peel strength)≦0.98 N/5 cm    -   X: 0.98 N/5 cm<(peel strength)

(3) Residual adherence: Evaluated as shown below based on the residualadherence after 14 days.

-   -   ◯: 85%≦(residual adherence)≦100%    -   Δ: 65%≦(residual adherence)<85%    -   X: (residual adherence)<65%

(4) Writability: Evaluated based on writing traces from a permanentmarker whose writing had been wiped off.

-   -   ◯: generally completely remaining    -   Δ: partially remaining    -   X: nothing remaining

(5) Printability: Evaluated based on print traces from an inkjet inkwhose printing had been wiped off.

-   -   ◯: generally completely remaining    -   Δ: partially remaining    -   X: nothing remaining

EXAMPLE 1

To 100 parts by mass of acrylic latex (acrylic acid(2-ethylhexyl)/methylmethacrylate/methacrylic acid=60/15/25 mass ratio, solids content 30mass %), 100 parts by mass of water was added, then 10 mass % aqueousammonia was added while stirring to obtain an aqueous resin solutionhaving a pH of 8.4. A silicone emulsion DEHESIVE 39005VP/39006VP(manufactured by Wacker Asahi Kasei Silicone Co., Ltd., number averageparticle diameter 440 nm, silicone constituent 50 mass %, a mixture ofSi—H group-containing silicone, vinyl silicone and a platinum compound)was added to the aqueous resin solution so as to give a silicone contentas shown in Table 1. Water was added to give a solids contentconcentration of 10%, then the solution was mixed and stirred to preparea release agent solution. This release agent solution was applied toKraft paper (82 g/m²) using a bar coater, then dried by a hot-air dryerat 140° C. for 5 minutes to obtain a release paper. After the obtainedrelease paper had been left overnight at 20° C., 65% RH, the paper wascut into 6 cm width and 10 cm length pieces to obtain test pieces forevaluation. The total application amount was measured from the weightgain of the test pieces, wherein the silicone application amount wascalculated using the silicone content. The evaluation results of thetest pieces are shown in Table 1.

EXAMPLE 2

Test pieces were obtained in the same manner as those in Example 1,except for the silicon emulsion being changed to a silicon emulsionSLJ1519 A/B (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.,number average particle diameter 100 nm, silicone constituent 50 mass %,a mixture of Si—H group-containing silicone, vinyl silicone and aplatinum compound). The evaluation results of the test pieces are shownin Table 1.

EXAMPLE 3

Test pieces were obtained in the same manner as those in Example 2,except for the alkaline used in the neutralization reaction beingchanged from 10 mass % aqueous ammonia to 10 mass % aqueous sodiumhydroxide. The evaluation results of the test pieces are shown in Table1.

EXAMPLE 4

Test pieces were obtained in the same manner as those in Example 1,except for the silicone emulsion being changed to a silicone emulsionDEHESIVE 400 E/V20 (manufactured by Wacker Asahi Kasei Silicone Co.,Ltd., number average particle diameter 180 nm, silicone constituent 48mass %, a mixture of Si—H group-containing silicone, vinyl silicone anda platinum compound). The evaluation results of the test pieces areshown in Table 1.

EXAMPLE 5

Test pieces were obtained in the same manner as those in Example 2,except for the composition of the acrylic latex being changed to acrylicacid(2-ethylhexyl)/methyl methacrylate/methacrylic acid=60/5/35 massratio. The evaluation results of the test pieces are shown in Table 1.

EXAMPLE 6

Test pieces were obtained in the same manner as those in Example 2,except for the composition of the acrylic latex being changed to acrylicacid(2-ethylhexyl)/methyl methacrylate/acrylic acid=60/15/25 mass ratio.The evaluation results of the test pieces are shown in Table 1.

COMPARATIVE EXAMPLE 1

Test pieces were obtained in the same manner as those in Example 1,except for acrylic latex being changed to SB latex(styrene/butadiene=41/56 mass % ratio, glass transition temperature 0°C., minimum film formation temperature 15° C., solid content 50 mass %),and the release agent solution being used as is, without neutralizingwith aqueous ammonia. The evaluation results of the test pieces areshown in Table 1.

COMPARATIVE EXAMPLE 2

Test pieces were obtained in the same manner as those in Example 1,except for the acrylic latex being used as is, without neutralizationwith aqueous ammonia. The evaluation results of the test pieces areshown in Table 1. TABLE 1 Composition/Application amount Silicone numberSilicone Evaluation results average particle Silicone application Changein peel Residual diameter content* amount** strength over adhesion nmmass % g/m² Releasability time ratio Example 1 440 20 1.4 Δ X Δ Example2 100 10 0.5 ◯ ◯ ◯ Example 3 100 20 1.3 ◯ ◯ ◯ Example 3 100 10 0.5 ◯ ◯ ◯Example 4 180 10 0.5 ◯ Δ Δ Example 5 100 10 0.4 ◯ ◯ ◯ Example 6 100 100.5 ◯ ◯ ◯ Comparative 440 10 3.0 X X X Example 1 Comparative 440 10 0.7X X X Example 2*Silicone content = Silicone mass (g)/(Silicone mass(g) + resin mass(g))× 100 (mass based on solid content)**Silicone application amount = total application amount (g/m²) ×Silicone content (mass %)/100

EXAMPLES 7 to 10

To 100 parts by mass of acrylic latex (acrylic acid(2-ethylhexyl)/methylmethacrylate/methacrylic acid=60/5/35 mass ratio, solids content 30 mass%), 92 parts by mass of water was added, then 5 mass % aqueous ammoniawas added while stirring to obtain a neutralized resin having a pH of6.5. A silicone emulsion SLJ1519A/B mixture (manufactured by WackerAsahi Kasei Silicone Co., Ltd., number average particle diameter 100 nm,silicone constituent 50 mass %, a mixture of Si—H group-containingsilicone, vinyl silicone and a platinum compound) was added to theneutralized resin so as to give a silicone content as shown in Table 1.Water was added to give a solids content concentration of 15%, then thesolution was mixed and stirred to prepare a release agent solution. Thisrelease agent solution was applied to Kraft paper (82 g/m²) using a barcoater, then dried by a hot-air dryer at 140° C. for 5 minutes to give arelease paper. After the obtained release paper had been left overnightat 23° C., 50% RH, the paper was cut into 6 cm width and 10 cm lengthpieces to obtain test pieces for evaluation. The total applicationamount was measured from the weight gain of the test pieces, wherein thecalculated silicone application amount using the silicone content was0.5 g/m². The evaluation results of the test pieces are shown in Table2. A transmission electron microscope photograph of a test piececross-section of Example 7 is shown in FIG. 1.

EXAMPLE 11

Test pieces were obtained in the same manner as those in Example 7,except for the silicon emulsion being changed to a silicon emulsionDEHESIVE 400 E/V20 (manufactured by Wacker Asahi Kasei Silicone Co.,Ltd., number average particle diameter 180 nm, silicone constituent 48mass %, a mixture of Si—H group-containing silicone, vinyl silicone anda platinum compound). The evaluation results of the test pieces areshown in Table 2.

EXAMPLE 12

Test pieces were obtained in the same manner as those in Example 7,except for the composition of the acrylic latex being changed to acrylicacid(2-ethylhexyl)/methyl methacrylate/methacrylic acid=60/15/25 massratio. The evaluation results of the test pieces are shown in Table 2.

EXAMPLE 13

To 100 parts by mass of acrylic latex (acrylic acid(2-ethylhexyl)/methylmethacrylate/methacrylic acid=60/5/35 mass ratio, solids content 30 mass%) 92 parts by mass of water was added, then 5 mass % aqueous ammoniawas added while stirring to obtain a neutralized resin having a pH of6.5. A silicone emulsion SLJ1519B (manufactured by Wacker Asahi KaseiSilicone Co., Ltd., number average particle diameter 150 nm, siliconeconstituent 50 mass %, a mixture of vinyl silicone and a platinumcompound) was added to the neutralized resin, and this solution wasstirred and mixed to obtain a release stock solution having a siliconecontent of 5 mass % in solids content. This release stock solution wasstored at 23° C. for 30 days, then added to a silicon emulsion SLJ1519A(manufactured by Wacker Asahi Kasei Silicone Co., Ltd., number averageparticle diameter 150 nm, silicone constituent 50 mass %, Si—Hgroup-containing silicone) to give the silicone content as shown inTable 2. Water was added to give a solids content concentration of 15%,then the solution was mixed and stirred to prepare a release agentsolution. This release agent solution was used to obtain test pieces inthe same manner as those in Example 7. The evaluation results for thesetest pieces are shown in Table 2.

EXAMPLE 14

Test pieces were obtained in the same manner as those in Example 7,except for the drying temperature after application of the release agentsolution to the Kraft paper being changed from 140° C. to 100° C. Theevaluation results for these test pieces are shown in Table 2.

COMPARATIVE EXAMPLE 3

Test pieces having a silicone application amount of 0.5 g/m² wereobtained in the same manner as those of Example 7, except that asubstrate that was laminated (film thickness 15 microns) by meltextrusion of low-density polyethylene (manufactured by Asahi Kasei) ontoKraft paper was used as the release substrate, and that a mixture of anaddition-reaction type silicone SD7220 and a curing catalyst SRX212CAT(manufactured by Dow Corning Toray Silicone Co., Ltd., toluene solution,silicone constituent 30 mass %) was used as the release agent solution.The evaluation results for these test pieces are shown in Table 2.

COMPARATIVE EXAMPLE 4

Test pieces having a silicone application amount of 0.5 g/m² wereobtained in the same manner as those of Example 7, except that a longchain alkyl pendant type polymer—pyyrole 1010 (manufactured by IpposhaOil Industries Co., Ltd., toluene solution) was used as the releaseagent solution. The evaluation results for these test pieces are shownin Table 2. TABLE 2 Release layer composition Evaluation results Surfacelayer Change in Silicone silicon atomic peel Residual content*concentration strength adhesion mass % atom % Releasability over timeratio Writability Printability Example 7 10 22 ◯ ◯ ◯ ◯ ◯ Example 8 20 24◯ ◯ ◯ ◯ ◯ Example 9  5 13 Δ Δ Δ ◯ ◯ Example 10 50 25 ◯ ◯ ◯ Δ Δ Example11 20 20 ◯ ◯ ◯ ◯ ◯ Example 12 10 23 ◯ ◯ ◯ ◯ ◯ Example 13 10 22 ◯ ◯ ◯ ◯ ◯Example 14 10 16 ◯ Δ Δ ◯ ◯ Comparative 100  25 ◯ ◯ ◯ X X Example 3Comparative — 0 X X X ◯ ◯ Example 4*Silicone content = silicone mass(g)/(silicone mass(g) + resin mass(g))× 100 (mass being solid content standard)

INDUSTRIAL APPLICABILITY

The release material according to the present invention allows forproduction using direct coating onto a substrate without requiring theapplication of an undercoating material even when using a permeablesubstrate such as paper. This material has excellent releasability evenwhen the amount of silicone used is small, has a low change in peelstrength over time, has a high residual adhesion ratio for an adhesivetape, seal and the like after release from a release material, and isexcellent in writability and printability to the release surface.

1. A release material comprising a substrate and a release layer on saidsubstrate, wherein a surface portion of said release layer has asilicone layer having a thickness of from 1 to 100 nm.
 2. The releasematerial according to claim 1, wherein the silicone layer of the surfaceportion of said release layer has a thickness of from 1 to 50 nm.
 3. Arelease material comprising a substrate and a release layer on saidsubstrate, wherein said release layer comprises a polymer having acarboxylate group and a silicone.
 4. A release material comprising asubstrate and a release layer on said substrate, wherein said releaselayer is prepared using: (A) a neutralized resin obtained from aneutralization reaction of an emulsion copolymer of a monomercomposition containing from 5 to 80 mass % of an unsaturated carboxylicacid monomer with a basic substance; and (B) a silicone emulsion and/ora silicone dispersion.
 5. The release material according to claim 4,wherein said (B) silicone emulsion and/or a silicone dispersion has anumber average particle diameter of 200 nm or less as measured bydynamic light scattering.
 6. The release material according to any oneof claims 4-5, wherein the neutralized resin is water-soluble.
 7. Therelease material according to any one of claims 4 to 6, wherein theunsaturated carboxylic acid monomer is acrylic acid and/or methacrylicacid.
 8. The release material according to any one of claims 4 to 7,wherein the basic substance is ammonia.
 9. The release materialaccording to any one of claims 4 to 8, wherein the neutralized resin hasa pH of from 3 to.
 13. 10. The release material according to any one ofclaims 4 to 9, wherein said release layer has a surface portion siliconelayer having a thickness of from 1 to 100 nm.
 11. The release materialaccording to claim 10, wherein said release layer has a surface portionsilicone layer having a thickness of from 1 to 50 nm.
 12. A releasematerial comprising a substrate and a release layer on said substrate,wherein the surface silicon atomic concentration of said release layeras measured by an XPS (X-ray Photoelectron Spectroscope) is from 10 to30 atom %.
 13. The release material according to any one of claims 1 to11, wherein the surface silicon atomic concentration of said releaselayer as measured by an XPS (X-ray Photoelectron Spectroscope) is from10 to 30 atom %.
 14. The release material according to claim 12 or 13,wherein the silicone content of the release layer is from 1 to 90 mass%.
 15. The release material according to claim 14, wherein the siliconecontent of the release layer is from 1 to 50 mass %.
 16. A releasematerial comprising a substrate and a release layer on said substrate,wherein the surface silicon atomic concentration of said release layeras measured by an XPS (X-ray Photoelectron Spectroscope) is at least 5times greater than the average silicon atomic concentration of therelease layer as calculated from the silicone content of said releaselayer.
 17. The release material according to any one of claims 1 to 15,wherein the surface silicon atomic concentration of said release layeras measured by an XPS (X-ray Photoelectron Spectroscope) is at least 5times greater than the average silicon atomic concentration of therelease layer as calculated from the silicone content of said releaselayer.
 18. The release material according to claim 16 or 17, wherein theaverage silicon atomic concentration of the release layer as calculatedfrom the silicone content of said release layer is from 0.2 to 4 atom %.19. The release material according to any one of claims 1 to 18, whereinthe silicone in said release layer is a curable silicone.
 20. Therelease material according to any one of claims 1 to 19, wherein thesilicone in said release layer substantially comprises a cured materialobtained from an Si—H group-containing silicone and a vinyl silicone.21. The release material according to any one of claims 1 to 20, whereinthe substrate is selected from the group consisting of paper, cloth,resin laminated paper, resin coated paper, a resin film, a resin tapeand a resin sheet.
 22. The release material according to claim 21,wherein the substrate is either paper or cloth.
 23. A release agentcomprising a polymer having a carboxylate group and a silicone.
 24. Therelease agent according to claim 23, wherein the silicone comprises asilicone in the state of a silicone emulsion and/or silicone dispersion.25. A release agent comprising: (A) a neutralized resin obtained from aneutralization reaction of an emulsion copolymer of a monomercomposition containing from 5 to 80 mass % of an unsaturated carboxylicacid monomer with a basic substance; and (B) a silicone emulsion and/ora silicone dispersion.
 26. The release agent according to claim 24 or25, wherein said (B) silicone emulsion and/or a silicone dispersion hasa number average particle diameter of 200 nm or less as measured bydynamic light scattering.
 27. The release material according to any oneof claims 23 to 26, wherein the silicone content is from 1 to 90 mass %based on the total solids content of the release agent.
 28. The releaseagent according to claim 27, wherein the silicone content is from 1 to50 mass % based on the total solids content of the release agent. 29.The release agent according to any one of claims 25 to 28, wherein theneutralized resin is water-soluble.
 30. The release agent according toany one of claims 25 to 29, which is prepared by mixing: (C) a releaseagent stock solution C, which comprises (c-1) a neutralized resinobtained from a neutralization reaction of an emulsion copolymer of amonomer composition containing from 5 to 80 mass % of an unsaturatedcarboxylic acid monomer with a basic substance: and (c-2) a siliconeemulsion and/or a silicone dispersion containing the vinyl silicone anda group VIII metal compound; with (D) a release agent stock solution D,which comprises a silicone emulsion and/or silicone dispersioncontaining a Si—H group-containing silicone.
 31. A method of producing arelease material, comprising the steps of applying the release agentaccording to any one of claims 23 to 30 onto a substrate and drying it.32. The method of producing a release material according to claim 31,wherein said drying is carried out at a temperature of from 100 to 250°C.
 33. The method of producing a release material according to claim 31or 32, wherein the substrate is selected from the group consisting ofpaper, cloth, resin laminated paper, resin coated paper, a resin film, aresin tape and a resin sheet.
 34. The method of producing a releasematerial according to claim 33, wherein the substrate is either paper orcloth.
 35. An adhesive tape comprising a substrate, a release layer onone side of said substrate and an adhesive layer on the other sidethereof, wherein said substrate and said release layer constitute therelease material according to any one of claims 1 to
 22. 36. A method ofproducing an adhesive tape, which comprises a substrate, a release layeron one side of said substrate and an adhesive layer on the other sidethereof, wherein the release material comprising said release layer andsaid substrate are produced according to the production methods of arelease material according to any one of claims 31 to
 34. 37. Theadhesive tape according to claim 35 or the method of producing anadhesive tape according to claim 36, wherein the adhesive layer is awater-soluble or water-dispersible adhesive, or an alkali-soluble oralkali-dispersible adhesive.
 38. An adhesive sheet comprising a releasesubstrate; a release layer on said release substrate; and an adhesivelayer and a surface substrate laminated on said release layer in thatorder, wherein said release layer and said release substrate constitutethe release material according to any one of claims 1 to
 22. 39. Amethod of producing an adhesive sheet, which comprises a releasesubstrate; a release layer on said release substrate; and an adhesivelayer and a surface substrate laminated on said release layer in thatorder; wherein the release material comprising said release layer andsaid release substrate are produced according to the production methodsof a release material according to any one of claims 31 to 34.